/Engine/Source/Runtime/GeometryCore/Public/DynamicMesh/Operations/SplitAttributeWelder.h
Weld split-elements at the ParentVID in each overlay that are "close enough" as defined by the appropriate threshold.
void WeldSplitElements ( [FDynamicMesh3](API\Runtime\GeometryCore\DynamicMesh\FDynamicMesh3) & ParentMesh, const int32 ParentVID )